Does "141" work for international calls from the UK?

[mrsurrey]

Not really a computing question but I have more faith in pprune's gurus than BT's website!

MrS

[airborne_artist]

If it works on your domestic calls (ring your mobile to check) it'll work on your intl calls, or upload some credit to a Skype account and ring from it?

[mixture]

MrS,

No easy answer, because it depends on many things.

However, theoretically your CLI should be deleted by the domestic carrier prior to handover to international carrriers when you set the presentation restriction indicator through 141.... i.e. in plain english, yes, in theory at least, it should work as intended.

You should bear in mind however, that once it leaves the carrier network they have no control. Therefore if they fail to delete CLI and simply pass on the presentation restriction indicator, there is no guarantee that this request will be upheld by the receiving international carrier(s).

[Jofm5]

mixture is pretty much correct.

Within the call data record information are two fields, network CLI and presentation CLI, if the call has been flagged as CLI Witheld BT will blank the presentation CLI as it is passed on to the subsequent networks.

However, it is a legal requirement for some countries that each call must have a CLI associated with it, thus other networks may put the network CLI into the presentation CLI to comply with licencing requirements.

If you really do not wish to be known you could use something like skype to make the call so that your BT Landline number is not known.

There is no easy way around this.

[mixture]

The "official" answer to your question probably lies in ITU-T Q.731 part 4.5.2.3.2.

Depending on bilateral agreement, the originating network may restrict the information conveyed in the generic number and/or calling party number parameter(s) from being sent to the destination network when the CLIR supplementary service is applicable.

The first few words "Depending on bilateral agreement" being the most important ones to remember, which is another way of putting what Jofm5 kindly pointed out.

[mrsurrey]

Many thanks! Where have you guys come from to have this knowledge?!

[Capetonian]

From my landline the default is not to send CLID. If I call my cellphone or another domestic landline it comes up 'number withheld', 'no number', or similar. Same if I call an overseas cellphone.

Here's the odd bit - if I call an overseas landline it comes up with 'international'. I don't like this as when I work from home I don't necessarily want people I'm calling to know that I'm not in the same country as them. I don't suppose there's anything I can do about this, just thought I'd throw it in to the pot.

[Keef]

I get "international" calls a lot from a friend 50 yards away. He's got one of those "internet telephones" as part of his broadband deal. Skype-out does the same.

Years ago, my CLI box would display the number of incoming international calls, but it doesn't seem to do so these days.

[Jofm5]

Capetonian,

When you make a call part of the signalling is a set of flags this will include whether to present the CLI and will also include the NOA (Nature Of Address) for both the calling party and the called party. The nature of address is typically national, International or Unknown.

The nature of address is required on a TDM network where you can dial national/local numbers - e.g. London to London - or London to Manchester. Due to least cost routing it is often required to convert the national number to an international number so that you can work out where in the world your billing points are (important if you have a global/mult-national network such as Worldcom or Interoute).

The mobile network which is displaying international and not your CLI is identifying this from the nature of address of your CLI to the remote network.

It is worth noting that over the internet H323 supports this as its based upon Q931 (ISDN) but SIP does not.